Global warming is shrinking a river vital to 40,000,000 people via @DanElliotAP SB:@MsALambert

In a study published in the journal Water Resources Research, they concluded that the rest of the decline is due to a warming atmosphere induced by climate change. The change is drawing more moisture out of the Colorado River Basin’s waterways, snowbanks, plants and soil by evaporation and other means.

Their projections could signal big problems for cities and farmers across the 246,000-square-mile basin. The area spans parts of seven states and Mexico. The river supplies water to about 40 million people and 6,300 square miles of farmland.

“Fifteen years into the 21st century, the emerging reality is that climate change is already depleting the Colorado River water supplies at the upper end of the range suggested by previously published projections,” the researchers wrote. “Record-setting temperatures are an important and underappreciated component of the flow reductions now being observed.”

The Colorado River and its two major reservoirs, Lake Mead and Lake Powell, are already overtaxed. Water storage at Mead was at 42 percent of capacity Feb. 22. Powell was at 46 percent.

Water managers have said that Mead could drop low enough to trigger cuts next year in water deliveries to Arizona and Nevada. They would be the first states affected by shortages under the multistate agreements and rules governing the system.

But heavy snow in the West this winter may keep the cuts at bay. Snowpack in the Wyoming and Colorado mountains that provide much of the Colorado River’s water ranged from 120 to 216 percent of normal as of Feb. 23.